Message-ID: <4019c5de3435de8e0c702e34c15d7000b2046e5b.camel@cybertec.at>
Subject: Re: insert into table with nest query
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: e-letter <inpost@gmail.com>, pgsql-novice@lists.postgresql.org
Date: Thu, 27 Apr 2023 11:28:03 +0200
In-Reply-To: 
 <CAET1fe5dXJGcvFFV=RzOQ3q+d-vVXK4k0ARb8QbA47Vyuv43nA@mail.gmail.com>
References: 
	<CAET1fe5dXJGcvFFV=RzOQ3q+d-vVXK4k0ARb8QbA47Vyuv43nA@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.46.4 (3.46.4-1.fc37) 
MIME-Version: 1.0
Archived-At: 
 <https://www.postgresql.org/message-id/4019c5de3435de8e0c702e34c15d7000b2046e5b.camel%40cybertec.at>
Precedence: bulk

On Tue, 2023-04-25 at 16:43 +0100, e-letter wrote:
> table1
> column1,column2
> value1,value2
>=20
> table2
> column2,column3
> value2, value3
>=20
> table3
> column1,column2,column3
> value1,value2,value3
>=20
> When value3 is first entered into table2, what are the correct
> commands for value2 (in table2) and value1 (in table1) to be selected
> for insertion into table 3?
>=20
> INSERT INTO table3 SELECT ... WHERE value3=3D'...';
>=20
> The conceptual difficulty is how to use nested query correctly, or is
> there a better method? Thank you.

The question is a bit unclear, but perhaps you mean

INSERT INTO table3 (column1, column2, column3)
SELECT table1.column1,
       table1.column2,
       table2.column3
FROM table1
   JOIN table2 USING (column2)
WHERE table2.column3 =3D 'value3';

Yours,
Laurenz Albe